Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> Do I understand correctly that what is needed to implement your
>> suggestion is
>>
>> 1. Remove case_fold_search_ slot from buffer objects
>> 2. Use DEFVAR_LISP for case-fold-search
>> 3. Declare case-fold-search buffer-local
>> 4. Replace BVAR(...) references in C with Vcase_fold_search
>
> Yes (assuming that 3 refers to the use of `make-variable-buffer-local`).

See the attached patch.

I used my `find-buffer-visiting' benchmark

(dolist (file (directory-files "/tmp/test/" t "txt"))
			   (find-file-noselect file))

Without the patch: 10.3 sec
With the patch:     7.0 sec

Without the patch, the reverse profiler tree is
        2728  26%   Automatic GC
        1187  11% + abbreviate-file-name                    ;; <---
        1080  10% + inhibit-local-variables-p               ;; <---
         913   8% + uniquify-rationalize-file-buffer-names
         816   7% + find-buffer-visiting
         547   5% + locate-dominating-file

With the patch, the `abbreviate-file-name' and
`inhibit-local-variables-p' no longer appear on top

        2559  35%   Automatic GC
         892  12% + uniquify-rationalize-file-buffer-names
         704   9% + find-buffer-visiting
         473   6% + locate-dominating-file
         295   4% + dir-locals--all-files
         241   3% + generate-new-buffer
         219   3% + file-truename
         169   2% + inhibit-local-variables-p
         128   1% + abbreviate-file-name